There once was a new articles by the Observer posted, but it appears it is no longer there. My grandmother experienced the tornado as it tore through and severely damaged Arkona, Ontario. My grandfather was an ironworker at the time in Sarnia and watched the tornado engulf the entire downtown core and disappear on the horizon as it headed out to London, Ontario. For the next three days, as my grandmother says, tornadoes were dropping out of the sky all over southwestern Ontario including one that went through the farms surrounding their property. Official reports have put this tornado as an F4. One of only seven known to have affected Ontario in the last 100 yrs.

Wikipedia article:
A tornado struck Sarnia, Ontario, Canada on May 21, 1953. One of the many violent tornadoes during the exceedingly active and deadly 1953 season, the tornado touched down shortly before 4:30pm near Smiths Creek, Michigan (10 miles southwest of Port Huron). It moved steadily towards the east-northeast where it devastated the southern edge of Port Huron (F3/F4 damage). Two people were killed in Port Huron and about 20 more were injured. Close to 400 homes were damaged or destroyed in the United States.

The tornado then crossed the St. Clair River into Canada, where it intensified and grew in size to 900 metres (approximately 0.5 mi, 0.9 km) in width. There was "great destruction"[1] to homes at Sarnia, Ontario where losses totalled $15 million. Four people were killed in Sarnia, 40 were injured, and 500 were left homeless. It then damaged more structures in Nairn before lifting in the Stratford area, although it is possible that this was a family of tornadoes rather than just one.http://en.wikipedia.org/wiki/1953_Sa...ntario_tornado